SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e406c9c9a372e2bd37062c85573a461a71291c398e2d51a874bcc8d321c5dda9' 
  AND token = 'qdHyl6tlCEzj3DaRPWL5I68X0pIfeRrsQRv8BCGR+Mc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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