SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9c7bf128f52e99c055274984a29f8fac09e76ae203a5590d7b244fb759020f5' 
  AND token = 'u5/sa1WDBPulZJoPz4gCGRPijPu2EKFWB0YO2vQnTqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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