SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '214fd1a359168cbee1d70e40fda301c8acf8d064c4067ea896ff5a13f5272766' 
  AND token = '1bpzXF4dgIrg6wKoi/0v9k3WZjAiiNFn5fQEO/usSCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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