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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '021f6aaccf1e5eff1c6241bb2633c38a03da71f02f2274284e9e6193611ad96e' 
  AND token = 'm1WMF+V5Hnovy1SIbrlSDfD2/Br13UCfhHtSFL9oQdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}