SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34b092d9360c451236d642ab90ea22af72e66e1bf1fa37aef70c830e00b2b193' 
  AND token = 'ERGvnNsrAShgZUkAGkMyWgNXLtkBAoP+UhTU9kyTZbI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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