SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9bce88c77c5ee11e0872bffdbfe21622b626882d6d2b66786513c27e6d88f3c' 
  AND token = '1DOMFIpvoZe0EldJ9ELtU0g8UCrqceSTknHJqmbOEak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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