SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9701bb0b65ae094d06cb51689211bfa92d3dfb5b0bdf9c350794b17341e77aff' 
  AND token = '+NCg2H26YJha9jP7CK3QJOAALVIWGISfTPUqasBeEZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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