SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c1c09b9b708775bbb2503a4026eef941b966397d26de3644cf799252f6c5f6b3' 
  AND token = 'fbhkfSx2Jn13l+/iFeBuWaWumwjRfibYWkSfSYiq+7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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