SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '525f6e916eb7b913d46cf3024da2aec7628cb5bb4f100b8f34db9558fd24b540' 
  AND token = 'dtWdCzjrzwVOayNeifTljo2prV9+06tj4YzvqSSTB5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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