SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fef720139a6434689df70f460b98411db19e6171c6e22f360d45269923347a42' 
  AND token = 'KX16YUQvWlYqPRogJatQRuEu8n/uBY8jWgDYjoSndcI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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