SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'effad4d34b76d7d0b2e5560ac14fd22f93c5376b6b8bbaa786dda1eb0f57637a' 
  AND token = '56ByJwHKk0hAkaRFzMmQhvvl+kjXpQGmwZcpbOgmQ/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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