SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd66a6bcfb7416d4abafef78f52fb6b0fd4a32fc4278fc34fe979906cc9a01814' 
  AND token = 'o+yBCs9nwjDUHW2AjPQjmyCNYOosvICX6cELztjxccs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}