SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '379f2740c48b85925ad31476a894d5cc95452cc18979841f593a44109f122b90' 
  AND token = 'QZqVn6x17X8CKQ+ZLFIUpO1Zdcq7XOFbNhz+RS/twNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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