SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '8687e3a461ddfa3c41b994a96dff8c0cc3497ff6c9d933aad560265e6d5b7f5e' 
  AND token = 'RV2dQiNi5+SuIHXQhgtSNz/oB7Zh9evCHBPG6LMTHR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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