SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86b138e228ae16c8378d31411c170cf543d239b7d2b74b2f51df69ce72783480' 
  AND token = '/XVYnsHSMJAZ/ENq/9/875I9WRbwSg5v95mmRxl+Qb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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