SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18728938ccb6718e62a7e76caaaa908212a65b481508aa1cefd274531cfce058' 
  AND token = 'GEzJ2WSSZQ5i5UjHOZ/GJHVvgAuiT2xjX3dCWWaST68=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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