SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49a26985753037306838f41f6053f58d0cbff337b2565247da210c330d2574b8' 
  AND token = 'rxqgVF1feYIBAkN4vx5fQKMNNHZx/SYQ4y80mW18l2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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