SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e90b9454a4f8f2738154307880136fd839acbed77680ad1687868531b5674f9' 
  AND token = 'nDzdlmh1Z4EIckPFoy3qqAyAuCYze+dEFmjicbckdFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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