SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a984fc601e862509155d7bb060fe44ee37a7beded204bdc2465f9fca311a91aa' 
  AND token = 'lqGq9zC7RYJc33fw0jmN/1IRJHBOtlZxuRFgmQpbGRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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