SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '535ee840a3e787365d57260d9f8034c7b405530169d61636f7284e106297a2b5' 
  AND token = '/AZIaZiOdArphaK1JgFxjSyVe1H/XI9eJYG7UUOtoJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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