SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d2bebc4551b1332cb6746535edb1050b4eead02ba59d3386f0fe34e0f36eb36' 
  AND token = 'eLGyH7IR8S8YHBUWWn3RhPzGm0K4KrPvTh4OnQrsiBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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