SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '838a6849291d7a9c2e84ffeef998a8e667bdaca11a46bcd480d184c2219a0bba' 
  AND token = 'kvDmsEN25m0T3TB8lMrmkOsWALdKoiF23GCpJq+pG+M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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