SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea3e013caa17c43b0dfb39a54ebec94972d9dfcba776d7da015cb85fba561c57' 
  AND token = 'u/ixAdxvHKFatWNBZPkZB51sGVbCrsUBmd8L2WhRvIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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