SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '959c2bf3dcd42ea0c694f0a781774c62f3e09c2da9e9254c2f37c23b0f7a7562' 
  AND token = 'UgAN1L4hrL+JpNvLbuGlAW6kQ5SmN+jaJw3+ChOmSwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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