SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '660354875258fb3b981373db566150321669d2db4a7518edeca5542bbfda52a8' 
  AND token = 'r4zTEyV4wO9N9uKcTpjRmWsq+DkYJCn6h1/lz/NA8G8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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