SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a5fae4a259de1969d5276b9db2d89489f6418d17123726c4bf0fb9eabcbecdc' 
  AND token = 'hnvcdHVDAeZyJMG97CALO5NpLxmJvpKCrsJKXR3k1ec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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