SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dce37dc6217a7d9f1068755f2cd1019b67a7b3c9fde5d8aa4cef53351480dec1' 
  AND token = 'KIsA8xSEn0MIczFsBkm6VHiQ/j929uKh2BIVjOBCOgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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