SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42ea271602d597187a189784c30cc1e20999b21ac994d19c7f84754656b0c3a0' 
  AND token = 'U4q9Wj8ORwYPTaOBqSoIlg881N85Wo4QQfIm1wRBwnM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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