SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af9644463f7df23eb27c4cfc34fd424565bfa3d88153d81f599756027763b55b' 
  AND token = 'dBESqzh262GfWhJw//sKKObD0gkn3lBQw/7bPDpNfgw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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