SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '13b4611be85d940409f2872302a77d13a8e622e0c9a99f40fb34f68d38a5f9b4' 
  AND token = '/2JoazDTFPbTFJiuMKmCo67W+k1t4YryJygnB8GdKQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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