SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae5b3450c967f8cf59676274783ddf686be3dbf00bd40a5aa1be314a60fc662e' 
  AND token = '0knRAWZVl85ayKjfJZKT6Tgzc7h8QmFrgYG9jEGztS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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