SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6423614589478d1bb4d75ae3cba97efb08ca291ab54365599cdf695ea8b2090e' 
  AND token = 've5/94xvWYHBWXwIcuNp6V1DWIEzqX+HhCLUdbarG3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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