SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '266b75bb9d51e7a2d7168d9695542cbc4b86e58eb30386feb3947bd0add47460' 
  AND token = 'ig1p45Io/6v88Z0ZoiEHOdR2AqAFKdisOebEsgYGcF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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