SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59078fce421c48e7ab327fc24fab65a49322ec15b6001aefe0034933083f83cf' 
  AND token = 'gIb8tmG+4FowP4UAiiVVo5jddXB6vl44sp8bUYN4WG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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