SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '619f2dc1e0f2595c8a0218e016be0aed9a11279785b6630a5da985ea5b34bdf2' 
  AND token = 'dsGlh+mp6SERj8lb31akGQqCzBjTYFaxbsQg/NcKzHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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