SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58f5efcdbe3ed5c40cb6f1eb8dda5788caf500289924fc377cd43a4078505989' 
  AND token = 'ExMHBjRnUD/jsc5NdSIH7eKpxH133rkW5U4srCqjmIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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