SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96e927afa366e838baf2a520d05bd4fb47472b60068dd525e63f054fbef1b2cd' 
  AND token = '7jmum4cW+AjxKmK4+ew+ambRpZ0cMoDIzH9+YxUZfQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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