SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eaedcf90d657dc24c338ed3f4ddc2943f1f9f01fa9c3f32d311f1e1f6d449658' 
  AND token = 'XQNnwyKmYf9RZaGm8mXB03phwcfKcBqKzQnxysQgh4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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