SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc19ab3013a869b3d34e39986f7b32db1790483f2fe03c912d23b651834a742a' 
  AND token = '+O1ceGUN8NqC3TRkBPLtoAaNy+uI0UQdOJIlH5WxNxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}