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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '174a1aeab7b0ad1ed25bd61c7ac67bc93d0d6a171c9ec283ec6ba2fa9af4535a' 
  AND token = '78pVCCmywEtsWK4tQxOBPB1RNG6LzNlXNPImPrur/WU=' 
  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"
    }
  }
}