SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3b6cf7bf0e7a724f0ad379330d6b8b325a8bb3b4ca16f99c8f292597f149279' 
  AND token = 'sYYoOGZZJWBG8vFo8kWXuCIumwEcZ7CTSr6plnBBQ/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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