SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d6911a66370e316961204466011da2a76e39c46bc5def68050f192403a1a7fb' 
  AND token = 'kmLJtUsCJwE+3y1fFCmPQzSBHzs7oCoSSJY0G2DIDXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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