SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99d8f7896bdb7d6da937b6e4b40237de764ca45b2ddefa0a1518f16e5f26730c' 
  AND token = 'SCFt8zmFrjZbQ/BihonR9tjlZG2msCElmrOEawhYW5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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