SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '725b2f63a68e410cae8857f35b99dff1908840cd9d35043adf52fecc34a370ca' 
  AND token = 'WevXKZkBJ3OuyotvqE9unnWCxlFzm29DF/oL3BV8mMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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