SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1736351c83577961624cc747deaf1b5148326bb9ecc88f2dd5ab7578cb873d51' 
  AND token = 'X/f8H6zwlv9hHY0R9a5Twwze4tnBquRi+RArUYTI76c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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