SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f7a364e82f4886d2cdfa4243688309e289bd00811b0490f2b09403b8d349fe56' 
  AND token = 'xwMcwBEbb5mjH3eYz+nkCnWJByreVf6Xqq0x7B/NAhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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