SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f7cc8161a80a6e015b225729a392d5fbb64d32fe524a5e4cae5cf423b96ef3e8' 
  AND token = '8lwPcv/28NN0ORszAW/5rANGkrDOJ2QlJufFql1h3oY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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