SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57af9aad5ba0ffa9650652ebd32001cdae3ab46c8675af685f3474d7e71dade7' 
  AND token = '2OR6xILwuMjFbU7UTIxh8GRWwBwH6WUXooYVic13YN8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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