SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0577b2bd428bb0aeca2b6dcf8f18676fa0dea6a0b7cc17a31d5da565937bc3a8' 
  AND token = 'a9XsYn6juByRFSe5JWWiKlrtGOvGOgeZwgtKE4BZuVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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