SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fe537b59c6181c47b4434c6b7613209faa5cd37e7c54b1747c94ec2e062329d' 
  AND token = 'O7gFk6Nu47+FfzzZ6fov2CCV7WQvI0fnxXq+khyR9oM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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