SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57982a2a7dc31bc1cc5d7296eb4557a4fbf8430913992fbd8a39f8543800d1bf' 
  AND token = '8ni5FE4F80rioPpzqVlS8fq5z2DiWlt8aG5fmOtFsIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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