SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e62b070b4fbbbc32a4020d17bbfb61735827805956609cffa0e11f5b33c989b2' 
  AND token = 'EAoMRiSqIV0FMQFSqpsvloRcmNzZwkHMVsdWdVI1NI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}