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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81ea669b0372f8d5c346ba56afaa58513c85e91e72a4870097fa8b8d0482a1c1' 
  AND token = 'PmD55w09gtwWKaanvQd1SWbmGP2dXFEXjCpBk5JKDUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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