Sandbox

SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b437c79bacbfb671145f390840e2f70ae997af128151da531f9d328a9e01b791' 
  AND token = '83rYJCArNgvefTiEJasC+YgaDgYYpggVop04tnio8Ls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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