SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d0195d8556ad470aa19a8be61e05fcce0f66b99cf4064eecdea3830f7cf5b12' 
  AND token = 'CnXdFIwFSguYB0vaC2h93MLvcrcSyht2fE5QUKWq+0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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