SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '173d418fecf8f733926c439d3b897eb172568031cf19041e4a99aacacfd44d77' 
  AND token = 'uJpVsRnYeebgHNtzeA9SBXu9cURCybFMsT6/835HYXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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