SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b1dbc98a462b941a72f0cb003c46e00ace1377c6a6f36bd182830efbb871294' 
  AND token = 'v+277evxicKdXD2sX+SMPLrNmIi3mW0BRQmsyktZarA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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