SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86374f90635bbd325ba4f675f91adb6cc49ad84fe137e693e77c8797d2504c93' 
  AND token = 'uAS3i4qQ3wNRSdejtHHSBKn4C0lD0InxXJtaancgxuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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