SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '00afcdd6d51f000b4cd11f0ca05acfec897aa74e971438fc419efa867f9384fe' 
  AND token = 'OByfvKSqGRI0ua0qaKv1r7PsXUmYqEAQ8VtPyk/dKCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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