SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b502f0e53f49197ba18715449942976b7aa88fe2832b322961536a3ced34332b' 
  AND token = 'orojIGKtGJej4EQT7sASMXbjtfPufAKg+v84OymXD8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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