SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'aa2231bba46b756ebbc2c29de4fffe94a26ecdc235b188887881699c49272b8b' 
  AND token = '1ZZymIDkW76X/U1uVq5Vo2vHCxaltr76/u9UN5XS3MY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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