SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f41257be39c91f9827fea13713b2b98e84d81185f42da1fb202ec40e8cb03a20' 
  AND token = 'vftJArYUotpmIMvGkQVrmZ4+izCQfG0NQFg27J0F0wk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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