SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '21852f8d33b300e3a4be65079acfb6f2c9218826fd2050ae41ec45af72576e29' 
  AND token = 'J25/nUBqAvF9HFOfpq/Gt0dkqDt00+XQaj06HuVA7mE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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