SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '642813f8246fe136d4f67985653d93f689ae4f1558f9e02445869176765f49ff' 
  AND token = 'Alq+mKK69Cx1DAtkCBvaRKJtQa+Jn9Pi09/ilIFnyNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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