SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '064af1b8fb488bb9eea259eb36c785ed9a06708d858f390233d2dd618178914e' 
  AND token = 'itosVaBrnXNqSgTisiwVj9YadrcuE5N0ajRFVdUnHfo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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