SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93c27c0573e2803bd9f73d32f2029ce87706770dcbccaefcf94dcac01db6d13f' 
  AND token = 'UUZYItsyOR2DyzRJW+ljlN/jdcknmJLZoPYJfdLIwrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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