SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1c20a07f15f6f30b247d63e296150f08a3c01522283e161a3a77d0e5d5923f85' 
  AND token = 'By6M+hJzWsNhC0CCCBnJmp17qfiojxhZ22VeAcuS7os=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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