SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c9a97c6871832613deb7e488098af2f39dd0deae9935d1cd25ee48d85787bdf' 
  AND token = 'VzNKYM96o/DiZFkSadWdmKu88Tz5OPbApPXulpxGJjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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