SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c6271553e93af6ae709f3eb45d6a7e5982457b9966414c301435fe15e5f656d' 
  AND token = 'sXKlm+a0CDMPo2MrxkWCqLdoQv5dzAessAeBmpzLVf4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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