SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6d66a836309e28958996a7943f77541698ef9dd2fc08b54cb5435e0fe710c95' 
  AND token = 'j+sGuIxdLQdOD+QtDzlReGWuCKMSz0qKCn3B/kAY2zw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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