SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43284f8dc4924b8b653764129cb204b4268cc0d81a30653b2f5b29a8febbca53' 
  AND token = 'XB8SwApAbTISLwpBI0qdXniWm9NHuXjyA1kpc7X8U4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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