SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '53a6228568d7442397be8c54678a0d9231c5d208f02334d78542784fd8c7a53b' 
  AND token = 'GWXtSnWpvOKDsa198FmYT2aRcuEv6tWaw3AD6OVd17c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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