SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a6a3d299a3347a543d8644fe66b6904d02715515d7108a6e41f647ac44d9572' 
  AND token = 'zuB6BZEEe/OlaDKKsIDozlizbBlpO87VjH4kV7+EEe8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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